Franny is an adventurous and restless ornithologist driven by a deep connection to the ocean and the natural world. Harboring a mysterious past and a powerful migratory instinct, she secures passage on a fishing vessel to track the longest migration of the planet's last remaining Arctic terns. Her wandering nature frequently conflicts with her desire for human connection, causing her to flee the places and people she loves most.

Niall is a passionate ornithology professor at the University of Ireland and an ardent climate activist. He holds deep pessimism regarding humanity's destruction of the environment but possesses a profound, accepting capacity for love. He understands Franny's wild instincts scientifically and personally, promising to always wait for her despite her frequent disappearances.

Ennis is the hardened captain of the fishing vessel *Saghani*. Operating in an era of severe commercial fishing restrictions, he obsessively chases a final massive catch to secure wealth for his crew. Beneath his weathered exterior, he is a compassionate leader who struggles to balance his maritime life with his family obligations.

Iris is Franny's mother, a woman highly sensitive to abandonment after being left by her own father and husband. She raises Franny as a single mother in western Ireland, establishing Franny's early connection to the ocean while carrying the heavy emotional weight of their isolated existence.

Dominic is Franny's father. Because he is absent throughout her upbringing, Franny grows up believing he simply abandoned their family, leaving her with unresolved questions about her heritage and the origins of her own internal restlessness.

Samuel is a gentle, Keats-reading crew member on the *Saghani*. Despite preferring quiet days of simple fishing, he endures the extreme dangers of commercial fishing in depleted oceans to provide for his large family back in Newfoundland.

Basil works as the cook aboard the *Saghani*. He is highly skeptical of Franny's presence on the ship and frequently clashes with her, expressing concern over the danger she brings to the crew and questioning the validity of her mission.

Edith is Franny's stoic paternal grandmother. She takes custody of Franny during her childhood and raises her on a farm. Though Franny initially views her as hard-hearted and unloving, Edith provides the only stable domestic environment of Franny's early life.

Léa is a hardworking crew member on the *Saghani*. She works grueling, long shifts maintaining the inner workings of the ship and bonds with Franny as they perform intense manual labor together.

Penny is Niall's wealthy mother. She maintains a large greenhouse filled with caged exotic birds and casts a critical eye upon Franny, viewing her daughter-in-law's free-spirited nature with overt suspicion.

John is Franny's maternal grandfather. Prone to intense jealousy over his wife Maire's wandering habits, he cast out his family long ago due to suspicions of infidelity, fracturing the family line.

Maire is Franny's maternal grandmother. Her tendency to disappear for days at a time provoked her husband's jealousy and mirrored the wandering instinct later seen in both her daughter and granddaughter.

Gammy is Samuel's wife. She manages their busy, loving household of six daughters and provides a glimpse of the stable family life that Franny simultaneously envies and fears.

Ferd is the six-year-old youngest daughter of Samuel and Gammy. She bonds quickly with Franny during the crew's visit to their bustling home, inadvertently reminding Franny of her own buried grief.

Anik is a crewman aboard the *Saghani* who engages Franny in discussions about the afterlife, expressing his belief in a beautiful, weightless spirit world where everyone eventually goes.